I don't think I would give up on those 600 LED's quite yet. I don't think this is an impossible task by any stretch. First let me give the caveat that I'm not any good at AVR assembly so I might be off base here.

The english data sheet varies from the chinese one google finds for the values of T1H and T1L (1.2u/1.3u versus 2.0u/0.5u). In either case it's a total of 2.5u for each bit. This works out to exactly 40 clock cycles (2500ns / 62.5ns) on the Arduino. The +/-150ns tolerance means that you can be over two clock cycles early or late for each transition. I don't think you can expect to write the loop in C++ and have the timing work out. But I think if somebody was reasonably proficient at assembly they could write a loop to manage this. The actual work to be done per bit is just two OUT instructions at 1 cycle each. That leaves 38 cycles for managing the loop itself. That should be plenty. You could unroll the inner loop over individual bits and inline that if you wanted. That gives you something on the order of 304 clock cycles to manage your loop over the bytes of data you want to output. That's tons of time. You can use SBRC/SBRS instructions to control the falling clock timing. Those instructions are nice because the timing is identical whether the condition matches or not.

The 2801's are very easy to work with though. I've got 350 of them up on my house right now as christmas lights. Let me know if you have any problems controlling them. I've got a hacked up version of shiftOut which is significantly faster than the stock one. You could also try the FastSPI library if you want to use SPI to drive them. The last batch I bought didn't work with FastSPI though and I didn't take the time to figure out why. I'm driving mine as four separate strands, so a single SPI line wasn't going to work for me anyway.

The fastspi library has code for the TM1809 LED driver which uses a clockless data line as well. Two clock cycles is well within the precision possible on an arduino or PIC if you disable interrupts for the duration of the write. The fastspi library simply defines two specific counts of nop instructions to insert into each loop to make the data sending work out right.

Sorry to dig up this oldish thread, but I too have a bunch of ws8211's, and I am determined to get them to work (preferably with the Pro Mini/Nano's as I have many of those too).

This thread is very puzzling as people are mostly saying that the SPI side is not possible, however, it works great with the FastSPI library. As long as my code is in the chip I can do anything I want with the lights, fairly fast if you ask me (a 5fps adalight would work fine for me). The problem is handling the serial port. I'm obviously having overruns there, and get very different results at different baud rates and all. I slowed it down to 2400baud, but it still doesn't work right. My super-simple well-commented code is below... the Startup Test works perfect, but Boblight (or even uploading a custom-made binary file through a terminal) is random and broken even at 2400baud upload, and all the delay(x)'s I could think of to try.

void loop() { // loop() is avoided as even that small bit of function overhead // has a measurable impact on this code's overall throughput. }

Can someone point me to some code for getting a SP interrupt working so it can fill a circular buffer that way an I can just pass the values to FastSPI? I tried searching everywhere and tried to reverse engineer LEDstream, but I feel a bit lost.

...or is this really not possible without a faster micro? I'd think since the LEDs work fine, it would have to be possible to pass serial bytes to them, even if I have to send, wait, send, wait one 153-byte frame at a time, at even 0.5FPS... it has to be possible!

I don't think you can do it. If you look at the timing you have to be accurate to 100nS and there simply isn't enough time in a 16MHz processor to do that, it turns out to be about two clock cycles. Even in machine code the overhead of reading data and producing those two diffrent waveforms times is too tight. I think you will have to have a diffrent processor, one that runs faster. Or a very fancy piece of hardware.

Why not have the Arduino write it into a RAM and then use a discrete circuit with a trigger and a precision timer to read the RAM when triggered and bitbang it out all purely using hardware? The biggest, bestest serial to parallel shift register evah. Sure, this is nasty overkill but at least it will prove you can make a nice little bespoke circuit.

I have only come here seeking knowledge. Things they would not teach me of in college.

Just as a note, the MSP430G2553 (available as part of the $4.30 Launchpad bundle) can run at least 60 of these things, despite being a 16MHz part.There's even a library for Energia (Arduino IDE ported to MSP430), here: http://forum.43oh.com/topic/2882-energia-library-ws2811driver-led-controller-class/#entry24208

And another note: there seems to be an assumption in earlier posts on this thread that if you use the FastSPI library to drive the WS2811 you are using SPI and therefore the WS2811 is a SPI device. That's wrong - when driving the WS2811 FastSPI uses bit-banging. Oh, and the timings aren't correct, which may be the issue if it doesn't work for you - see the blog post linked to above for details.